Digital transmission apparatus particularly adapted for security systems
First Claim
1. In a security system of the type employing a transmitter capable of transmitting a signal containing information as to the address code of a secured location by monitoring the opened or closed status of a loop associated with said location and transmitting said signal when the status of said loop changes, said signal containing additional information indicative of the loop status, and a remote receiver capable of receiving said transmitted signal, the combination therewith of apparatus located at said receiver and operative to monitor the total number of loop openings and closings, comprising:
- (a) means responsive to said received signal for storing therein said information associated with said address code and said loop status,(b) means for comparing said address code with a predetermined code stored in said receiver and indicative of said transmitter location, to provide a comparison signal when said codes are equivalent, and(c) means responsive to said comparison signal for storing said information indicative of said loop status, said means including a status counter effective to increase the count stored for one loop status and to decrease the count stored for said other loop status, whereby at the end of a desired period, the counter has stored therein the present status of said loop.
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Accused Products
Abstract
A digital transmission system comprises a transmitter and a receiver for use in a security system. An alarm code is set by means of switches in both the transmitter and receiver and is indicative of the address or location of a monitored location. The location as monitored contains a sensor which is in either an opened or a closed condition indicative of a secure or unsecure status. The transmitter operates to transmit a digital code for each change in the status of the loop. The code contains bits which define the alarm code or address, while additional bits define the loop status as opened or closed in conjunction with the condition of a battery which is used to power the transmitter. The receiver is adapted to receive the transmitted signal and is operative to compare the transmitted address with the code stored or programmed by the receiver switches. If a valid code is received within a predetermined interval, the receiver operates to decode the loop status by means of an updown counter. If the loop has been opened and closed the same number of times, the updown counter will indicate a secure position at the end of the day. The receiver also contains circuitry to monitor the battery status as transmitted within the code and to sound an alarm if the battery condition falls below an acceptable value. Due to the large number of possible code combinations and due to the modulation scheme employed, the system provides discrimination between other transmission systems operating within the area.
71 Citations
14 Claims
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1. In a security system of the type employing a transmitter capable of transmitting a signal containing information as to the address code of a secured location by monitoring the opened or closed status of a loop associated with said location and transmitting said signal when the status of said loop changes, said signal containing additional information indicative of the loop status, and a remote receiver capable of receiving said transmitted signal, the combination therewith of apparatus located at said receiver and operative to monitor the total number of loop openings and closings, comprising:
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(a) means responsive to said received signal for storing therein said information associated with said address code and said loop status, (b) means for comparing said address code with a predetermined code stored in said receiver and indicative of said transmitter location, to provide a comparison signal when said codes are equivalent, and (c) means responsive to said comparison signal for storing said information indicative of said loop status, said means including a status counter effective to increase the count stored for one loop status and to decrease the count stored for said other loop status, whereby at the end of a desired period, the counter has stored therein the present status of said loop. - View Dependent Claims (2, 3, 4)
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5. An information signaling system for a transmitter and receiver to enable a selected receiver to respond to one of a plurality of transmitters comprising a transmitter capable of transmitting an RF signal containing a binary code and having a first interval indicative of a signal start condition, and followed by a series of pulses and relatively equal time durations with said durations less than said start interval, with certain of said pulses indicative of a binary one containing a higher frequency tone within said time duration, means located at said transmitter for selecting an address code;
- which code is specified by said series of pulses, a receiver tuned to said RF signal and including means responsive to said start interval to cause said receiver to store said series of pulses, means located at said receiver for selecting said code associated with said transmitter and for comparing said code as selected with said series of pulses as stored to provide an output signal upon a favorable comparison, said receiver including means responsive to said higher frequency tone indicative of said binary one to enable said receiver to store said pulses as a binary code consisting of a series of ones and zeroes.
- View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14)
Specification